The nuclease-resistant, primate-effective interferon inducer, poly inosinic polycytidylic acid, poly lysine, carboxymethyl cellulose (Poly ICLC) has a variety of physiological activities. In addition to inducing interferon in primates, it is an immune adjuvant and a radioprotective agent. It is currently being evaluated in 3 collaborative clinical studies, and 3 more are being developed. It appears to have had ameliorative effects in 4 patients; one with lymphoblastic leukemia, one cancer patient whose widely disseminated Herpes lesions disappeared after treatment, and 2 patients with chronic relapsing polyneuropathy. A drug without carboxymethylcellulose has been prepared and is being evaluated.